I've had that issue with e85 a couple times. One time it was cured by running 180 water temp. The lower the compression the more temp it wanted.

Chased another on e85 and wound up having someone wack the throttle while using 2 spray bottles with e85 in them, and shooting extra fuel in at the same time. Came right up, so we were already at max on the pumps, so fattened up the idle circuit a bunch and went small on the bleed too. Like just a dart was saying

I've been using vp C85 exclusively for a while now, and I'll never go back. Runs like gas, great cooling, and zero corrosion. Makes way better power than pump too. Straight up on the break in everything so far